Passing the Smell Test :: Throughout the living world, the nose leads the way, pioneering a course through the environment with the ability to spot virtually invisible perils and prizes. by Eric Sorensen

Essay

Taste, an Accounting in Three Scenes :: I’d be lying if I claimed not to prefer the golf swings of Bobby Jones or Sam Snead to that of Tommy “Two Gloves” Gainey. So I guess I’m a snob. by Bill Morelock ’77

Washington State Magazine

Spring 2013

Features

Carolyn Ross demonstrates her “electronic tongue,” which can measure basic tastes. But as it requires extensive preparation of samples, can measure only one thing at a time, and cannot measure texture, it will not replace human evaluation any time soon. Zach Mazur

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Taste+aroma=flavor

Taste all by itself is what you experience when you have a really bad
cold clogging the pathways that sense the more elusive aromas, says
sensory scientist Carolyn Ross.

Sweet, sour, bitter, salty, umami. Sure, they’re fundamental and
promise seemingly endless combination potential, but a cold is a good
reminder that basic tastes without the subtler flavors can get pretty
boring.

Fortunately, we normally have two chances to experience flavor: before we taste and in conjunction with taste.

The initial aromas of a wine or an apple go up your nose, referred to as orthonasal olfaction.

You experience those aromas again once the wine is in your mouth, the retronasal.

You will taste the wine’s sweetness, acidity, and slight bitterness.
But the true pleasure of a fine wine lies in its more subtle aromas.

Much of your experience of aroma, says Ross, is played against
previous experience. Whereas taste derives from a more fundamental
survival origin, the sense of smell—the detection of aroma—is more tied
into the limbic system and thus more associated with memory and
emotion.

“When you smell something, you might recognize it or it reminds you of something, but you can’t quite put your finger on it.

“It’s called ‘on the tip of your nose’ in the sensory literature,” she says, smiling.

Humans have about 10,000 taste buds,
variously distributed, mostly on the tongue, which detect the five
basic tastes. Rabbits, on the other hand, have about 17,000 taste
buds. Cows have 25,000. And catfish? 100,000.

Before you feel gustatorially or evolutionarily slighted, however, you should know that the chicken has only 17.

And we might consider what these numbers are all about. Think, for
example, about the catfish’s general situation. A bottom-feeder, the
catfish must search through the gloom and muck for anything edible, let
alone nutritious and delicious. It needs a lot of taste buds, many of
them on its whiskers, to find its food in a muddy river bottom.

Given that cows consume primarily grass, one can only imagine the
varieties of flavor and corresponding nutrition spread across ancestral
grasslands that ultimately required that many taste buds to give cows
their current discretion.

And given that humans are broadly omnivorous, feasting on an enormous
range of food, from berries to pork chops, those 10,000 taste buds
seem to have served us well indeed, at least from an adaptive and
survival perspective.

Although we have only one or two taste receptors for sweetness, we
have dozens for bitter, strongly suggesting that our tastes developed as
a means of survival. Sweetness, a complex of many chemicals,
indicates energy-rich nutrients, which are particularly important for
feeding our brains.

Salt indicates necessary ions for electrolyte balance.

Bitter, on the other hand, generally indicates toxicity in the wild
in many forms. Bitter compounds can include everything from peptides
and esters to terpenes and methylxanthines like caffeine. Whereas one
can taste saltiness at a concentration of one part in 400, bitterness
can be detected at a concentration of one in two million.

Sour taste comes from acids, which can indicate both fermentation and
rot. It can be tasted at a concentration of one in 130,000.

Umami, the most recently identified taste, indicates the presence of
amino acids such as one might find in cheese or meat broth. Umami is
generally savory.

For those of us who eat and imbibe for reasons beyond mere
subsistence, those survival mechanisms have combined with the olfactory
detection of subtler aromas and volatiles to give us flavor.

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Much of Carolyn Ross’s work involves training people to quantify
their taste. The sensory evaluation panels that she and her graduate
students organize assess taste attributes in fruit and other foods and
beverages such as sweetness, acidity, bitterness, and astringency. And
“mouth feel,” which contributes enormously to the taste experience.

But for these panels to arrive at a consensus of, say, how sweet a
given apple is, or how tart, or how much it crunches in relation to
other apples, everyone must agree on the intensity of those attributes.

Before the panel members can evaluate a given food, they will train
for a number of sessions, tasting slivers of the same apple, for
example, then going through an evaluation procedure, assigning each
attribute a score on a 15-centimeter scale, over and over. Individuals
must often adjust their scores to match the group’s consensus, until
finally, they pretty much agree on how tart that fruit is, how
astringent, or how sweet. And then they will use those newly agreed upon
standards to evaluate a given product.

Similar work is conducted throughout the cheese world. Tasting is an
essential part of the WSU Creamery’s daily routine. MaryAnne Drake ’96
PhD heads the sensory evaluation program at North Carolina State
University, which specializes in dairy products, and has developed a
cheese flavor wheel and an exhaustive lexicon for cheddar cheese.

The object of Ross’s scrutiny may be a raspberry newly released by
Puyallup breeder Patrick Moore. Or a wine aimed at a specific segment of
the market. Or an apple moved forward in apple breeder Kate Evans’s
trials. The sensory evaluation of Cougar Gold, on the other hand, will
never produce another version, but rather ensure that it always tastes
the same. Thus, the perfect pairing will endure.

So many apples...

Although the apple has found its way into thousands of preparations,
both sweet and savory, the whole unprocessed apple is still its most
consumed and appreciated form.

But much has changed over the last decade or so. For years, the Red
Delicious ruled, particularly in Washington. Although it originated as a
chance seedling in Iowa in the nineteenth century, it adapted
beautifully to Washington’s growing conditions. In fact, so confident
was the Washington apple industry in the “Red” that the state did not
even bother with a breeding program. At its height, the Red Delicious
represented more than 60 percent of the Washington apple crop. (Although
it has dropped to approximately 34 percent of the state’s crop, it is
still the most widely grown variety. Indeed, there are still older
strains of Red Delicious, not the purest red, that are quite good.)

And then, a couple of things happened. Over the years, growers became
so enamored of the Red’s color that they selected sports, mutant
branches bearing redder apples, which they propagated toward a redder
and redder fruit. (The original Red Delicious, the Hawkeye, had red
stripes over a yellow-green background.)

A funny thing happens as an apple gets redder. Its flavor decreases.

Although others had started to grow concerned over how little flavor
remained in this admittedly gorgeous apple, it was post-harvest
horticulturist John Fellman who figured out what was happening.

“We proved...that as they selected for color, there’s only so much
metabolite to go around. Since the pigment is in a subset structure
called the vacuole in the skin, metabolite gets grabbed and stuck as
color.

“As that happens, it means less of the common metabolite for aroma chemicals.”

At the same time, after years of decline in the diversity of apple
varieties available in the market, people started to realize that there
were indeed apple tastes other than the sweet cardboard that the
reddest of the Reds offered. Marvelous-tasting apples from New Zealand
started appearing in the grocery store, in late spring and early
summer. Suddenly, stores that had once been limited to Red Delicious
and the unrelated Golden Delicious started offering people a steadily
growing choice.

Some growers became uneasy and started thinking outside the Red
Delicious apple box. And Bruce Barritt, a raspberry breeder in Puyallup,
moved to Wenatchee to start planting seedlings toward creating a
Washington apple-breeding program.

Twenty years later, WSU’s current
apple breeder, Kate Evans, sits at a large counter covered with scores
of apples waiting to be tasted. Yellow, green streaked with red in
multifarious combinations, red with hints of green poking through, the
apples are but a small sample of the offspring of Evans’s breeding
program. Every Thursday throughout the fall here at the Tree Fruit
Research Station in Wenatchee, she and her laboratory assistants taste
the fruits of their labor, searching for the next big thing.

The apples are a combination of seedlings, apples never tried before,
apples that have been carried forward in the breeding trials, and
controls. The Gala generally serves as a middle-of-the-scale control,
both for production systems and sensory evaluation.

Evans is part of a large multi-scientist, multi-university, and USDA
project, RosBREED, which aims to better understand the genomes of
fruit throughout the Rosacea family, which includes apples, peaches, and cherries.

One of the initiatives within the project is to identify flavor gene
markers. Geneticist Cameron Peace has been hunting down such markers
in the apple that may eventually give breeders more control and
precision in creating new varieties with desired flavors.

“The holy grail,” says Fellman, “is to have a whole suite of these
markers for breeders, so they can select without taking seven years to
get fruit.”

But that grail is so far undiscovered. In terms of aroma and
volatiles, markers have proven elusive. However, says Evans, she does
use such markers that indicate acidity.

“We have a couple of markers at a site on the genome, an area which
has a lot of fruit quality traits,” says Evans. That area includes a
gene for malic acid, the principal acid in apples.

“There seems also to be some control of juiciness and crispness in
that area, so it’s a really interesting section of DNA that has got a
fairly large contribution to fruit quality.”

Even once the markers are identified, using that knowledge does not
mean a breeder can simply pick a promising gene and insert it in a
seed. Rather, it is a means of better understanding what traits are in
the germplasm. Evans uses the marker for acidity to weed out
seedlings with insufficient acidity at the beginning of the selection
process.

“We’re more interested in applying it early, so we can screen out
poor material without having to spend time and money propagating and
growing them out for several years, putting them out in an orchard and
waiting for the fruit.

“It’s much more efficient.”

So far such selection has been at the very beginning of the process.
Evans does not use the information to move a candidate from phase one
to phase two of the breeding program, simply because identifying a
marker is only part of the overall picture.

“But it is something that Cameron is working on in terms of what he
calls ‘decision confidence,’” she says. “He’s hoping that by putting
more molecular data in with data that we’re producing from tasting or
instrumental measures it will help make a more complete case to
industry.”

The perfect pair

To some extent, looking for the perfect apple means looking for a
perfect balance between acidity (tartness) and sweetness. A merely sweet
apple may please some palates, but is really quite boring. (Though
I’m told there are actually people who like the Fuji.) With nothing to
offset the sugar, an apple lacks depth and dimension. It is flaccid
and dull.

A merely tart apple, on the other hand, can be equally unsatisfying.
The Granny Smith, a New Zealand apple that gained favor with the
American public when all the good American cooking apples had
disappeared from the market, is also generally picked too early and is
just sour.

But when an apple is balanced sweet and tart—a well-ripened Golden
Delicious, the Braeburn, Pink Lady, and WSU’s new offerings, as yet
unnamed—one realizes that perfection is indeed attainable here on
earth. Particularly when enjoyed with our own Cougar Gold.

Cougar Gold is what we do best. In searching for a culture to offset
the production of carbon dioxide in a cheddar cheese so that it might
be packed in a can and sent to troops in Europe, N.S. Golding, a
professor of dairy husbandry, inadvertently discovered the “magic
flavor culture” that moves an otherwise solid cheddar into the highest
realms of cheese possibility.

The task of keeping it Cougar Gold, which represents 80 percent of the Creamery’s sales, is not an easy one.

Russ Salvadalena, the director of the WSU Creamery, thinks of his
operation as both artisanal and fairly large. What distinguishes it from
many of the smaller cheese-making operations around the state is its
diligent quest for consistency.

Surprise can be wonderful in an artisanal cheese. Yeast and bacteria
abound, hanging out in nooks and crannies, floating through the air,
waiting for the opportunity to alter a cheese’s flavor.

What sets the Creamery apart from more industrial operations, many of
which obviously produce very good cheese, is not only its unique
quality and flavor, particularly of Cougar Gold, but also, again, its
consistency.

When an eager customer opens a can of Cougar Gold, what he or she anticipates is exactly that: the taste of Cougar Gold.

Every day the Creamery folk analyze the milk that comes in from the
campus herd of Holsteins, for butterfat and protein. Butterfat content
is the easier to adjust, by adding cream.

Various factors throughout the year, including the feed the cows are
eating and the temperature, can affect the milk’s composition.

Once the milk is deemed appropriate, rennet, an enzyme, is added to
break down part of the protein and enable the proteins to bind together
around the butterfat globules.

A cheese culture of lactic bacteria is also added. This is actually
one of four cultures that are rotated through the cheese-making cycle,
says head cheese-maker Nial Yager. The reason the Creamery maintains
four cultures, all of which do lead to the cheddar cheese that is the
foundation of Cougar Gold, is their archenemies, the phages. Phages are
viruses that attack the lactic bacteria and bring the fermentation of
the milk to a halt.

Besides an extreme attention to cleanliness, Yager and his staff
rotate the cultures, enabling them to prevent the phages, which are very
specific to the individual cultures, from building up.

What sets Cougar Gold apart from an ordinary cheddar is what Yager
refers to as their “magic flavor culture,” the one discovered by Golding
and nurtured carefully over the past 75 years.

This culture, a trade secret, breaks down the proteins in the cheddar
cheese even further, mellowing the acids and giving it that unique
Cougar Gold flavor.

Yager and staff transfer the culture from the mother culture to a
culture bottle every two or three days, doing so in an isolating glove
box to avoid contamination.

As an emergency backup, the culture is also preserved in liquid nitrogen at an undisclosed location on campus.

An added, and essential, daily task is to taste and evaluate the flavor culture to make sure it has not changed.

Although larger, more industrial cheese producers create good cheese,
it is the hands-on labor, provided by student workers, that sets
Cougar Gold apart, says Salvadalena. The “cheddaring” process is labor
intensive. Once the developing cheese has coagulated, salt added to
slow the fermentation, the curds cut, and the whey drained, the slabs
of new cheese go onto the finishing table, where the workers cut and
flip them continually until ready to drain and press and place in the
cans. It is this process that gives Cougar Gold the needed attention
to achieve the daily consistency.

Large cheese producers make their cheddar with an automated machine
called the Cheddar Master. Whereas the Creamery produces one batch a
day, the larger producers may do 30. Even under the best conditions, the
action of bacteria can alter over the course of a day, and each batch
might be slightly different in flavor.

Now, if you may, open a can of Cougar Gold. First, slice off a small
bit and chew it slowly: creamy, salty, sharp, nutty, a little bitter.
You may notice little crystals, tyrosine—an amino acid and the remnant
of casein, the main protein in milk—breaking down.

Now take a bite along with a sweet-sharp Washington apple. This is as good as it gets.

What is a Washington apple?

Washington’s excellence as a place to grow apples is reflected by the
fact that we produce better than 60 percent of the U.S. apple market.

“Cool nights and warm days and long hours of sunlight,” says
Fellman, summing up our climatic advantage. But there are subtleties
involved. Because our nights get so cool during fruit maturation, he
says, the carbon produced through photosynthesis during the day is
preserved by the plant. It does not get used up through what is called
maintenance respiration at night.

“So your net photosynthesis gain is very good, which is why things grow so well here.”

Even so, there is some truth in Fellman’s overstatement. Altering a
plant’s genetic signature always involves some tradeoffs. An apple
might be the most delicious thing in the world, but if it does not
ship well or hold up in storage or if it turns to mush three weeks off
the tree, that wonderful flavor alone is not going to make anyone any
money.

Indeed, to an extent, such is the case with many older varieties of
apples. Varieties such as Smokehouse, Wealthy, Belle de Boskoop,
Calville Blanc d’Hiver, and many others have wonderful, complex, and
tantalizing flavors right off the tree, making them excellent for a
connoisseur’s backyard or local farm market. Indeed many older uniquely
flavorful varieties are making a comeback, but if they don’t keep or
travel well, no large grower with a bottom line in mind is going to
plant them.

Developing an apple that tastes great and keeps well is Evans’s
challenge. And that challenge has grown greater with the increasing
competition, Washington- and foreign-grown, in the market.

Add to that the challenge of producing a variety for Washington
growers that stands out in the market. Not only must it taste great, it
must grow well here, it must look great (the wow factor), and people
must pay for it.

And they will take a bite and say, that must be a Washington apple!

Evans starts her breeding from varieties that do well here, she says. Typically, more varieties do well here than not.

“We look at the parents on an annual basis, look at how the fruit is doing and how the parents are performing in our climate.”

But that is hardly straightforward. Even central Washington, where
most of our apples—and grapes—are grown, is hardly homogeneous in terms
of climate, soil, and other environmental factors.

Indeed, the test sites that Evans uses are fairly extreme, but they
reflect the diversity of growing conditions. For Phase Two selections,
sites include an organic orchard at Lake Chelan—high elevation, cold,
exposed, late-blooming and late-maturing—and a site down toward
Richland, which is very hot and early.

When an apple is chosen for Phase Three, which currently includes
four “elite” selections, the sites become even more demanding: Brewster,
Quincy, Mattawa, and Prosser.

But beyond the challenges of producing a delicious and profitable apple, Evans believes the importance of flavor is coming back.

The threats to flavor are great, prime among them mass production and consumer expectations.

“We want our fruits and vegetables all year,” she says. “We expect to
have strawberries and tomatoes all year round, expect apples all year
round.”

In order to satisfy those expectations, apples are treated with 1-MCP
(methylcyclopropene) to retain texture throughout storage. 1-MCP
inhibits apple sensitivity to ethylene, a chemical produced by the apple
itself that induces ripening. 1-MCP thus delays not only softening,
but aroma production.

Fruit produces flavor volatiles only when it matures, Evans says. So
producing fruit on such a scale is inevitably a great compromise.

But Evans seems primed for the challenge. In spite of the odds, but
also with improving horticultural and genetic tools, Washington apples
will continue to prevail.